With the increasing environmental concerns, a paradigm shift towards electric and hybrid electric vehicles is expected. Switched Reluctance Motors (SRMs) have emerged as a viable competitor to other established electrical machines. SRMs are known for their simple construction, robustness, inherent fault tolerant structure and low production and maintenance costs. Moreover, the machine has gained interest due to the absence of permanent magnets or windings in the rotor structure, which significantly reduces production costs when compared to other electric motors. The SRM, however, present some known drawbacks, such as increased torque ripple and acoustic noise production, as well as a highly nonlinear behaviour. Through the use of adequate control strategies, however, the main challenges of the machine can be overcome. Thus, this paper presents a state-of-the-art review of the advanced control of SRMs, encompassing current regulation strategies, torque control strategies and vibration suppression techniques. First, two-categories of current controllers are reviewed: model-independent and model-based. Next, indirect and direct torque control methods are explored. Then, three approaches to vibration suppression are discussed, namely active cancellation, current profiling and direct instantaneous force control. Lastly, a summary of each topic is presented and suggestions of future research topics are listed.

This article presents a general-purpose full-speed sensorless control scheme for interior permanent magnet synchronous motors (IPMSMs). By applying a quadratic extended back electromotive force (QBEMF) model, the injection-based and model-based position estimations can be combined into a universal sensorless control strategy for the full-speed operation. At low speed, the QBEMF model acts as a self-demodulator that can extract position information from arbitrary high-frequency currents without using digital filters. Therefore, it is suitable for any type of injection signals and can eliminate the adverse effect of filters. When the injection is removed at high speed, the same QBEMF model can still be used for position estimation, thereby solving the conventional transition issue from low-speed to high-speed sensorless control. In consequence, a unified algorithm is designed to achieve arbitrary injection for low-speed sensorless control and seamless transition across full-speed region. The proposed scheme is hence simpler and more effective compared to conventional full-speed sensorless methods. Finally, the feasibility of the proposed estimation algorithm is verified for a 15-kW IPMSM drive.

This paper proposes a new sensorless control scheme of interior permanent magnet synchronous motors (IPMSM) using high-frequency (HF) orthogonal square-wave voltage injection into stationary reference frame (SRF). This scheme is an improvement on the conventional HF rotating sinusoidal voltage injection into SRF. Firstly, discrete sequences of HF currents are applied to establish the whole signal process. Then, a position estimation method without using low-pass filters is proposed and the phase shift caused by high-pass filter is also reduced. Therefore, the proposed sensorless control method would not be adversely affected by digital filters, which can solve the common drawbacks of the current SRF-based injection methods. Furthermore, digital delay in drive systems is considered and its negative influence can be eliminated effectively as well. The sensorless control method is verified by experiments on a 2.2-kW IPMSM drive platform.

Rotor position and speed estimation methods are consolidated to reduce the cost and volume of permanent magnet synchronous motor (PMSM) sensorless control drives while maintaining high performance. Advanced nonlinear algorithms require accurate design for precise estimation tracking throughout the entire PMSM operation range. This paper presents a broad review of the main high-speed estimation methods for sensorless PMSM drives. First, the stability constraints and design methodologies of the main estimation techniques presented in the literature are discussed. In the second part, it is investigated the new observer design trends, which are used under non-ideal conditions, such as robustness to distortions, the effects of parameter variation, sensorless parameter estimation, and low sampling-frequency-to-speed ratio operation. Future trends on the design of observers for high-speed sensorless PMSM drives are also discussed.

Aiming at tolerating common electric faults of multiphase motor drives comprehensively and minimizing the adverse impacts from the remedial scheme itself, a diagnosis-free self-healing scheme is put forward for the open-circuit faults of dual three-phase permanent-magnet synchronous motor (PMSM) drives. Firstly, the self-healing mechanisms of dual three-phase PMSM drives are analyzed in detail. On the basis of theoretical analysis, the repressed self-healing capability of the dual three-phase PMSM drives is fully released by optimizing the current references on harmonic subspace. Since the diagnosis process is not required in the proposed self-healing scheme, the misdiagnosis problem and the prolonged damage caused by the additional time cost of diagnosis can be fundamentally avoided. The proposed self-healing scheme can be generally applied to open-switch faults, single open-phase faults and multiple open-phase faults in the multiphase motor drives. No change is required for the machine model, modulation strategy or control framework under different open-circuit faults. Thus, the complex transition strategies among different fault-tolerant control methods for different faults can be avoided, and the adverse impacts from the remedial scheme itself can be minimized. Experimental verification is presented to prove the validity of the proposed self-healing scheme.

Switched reluctance motors (SRMs) are promising traction machine candidates for electric vehicle powertrains and industrial driving systems due to their rugged construction and high efficiency. Precise speed and torque control of SRMs require real-time rotor position information from mechanical position sensors. With the advantages of lower costs and position sensor fault-tolerant capability, various position-sensorless control strategies have been developed for SRM drives in the past decades. This article presents a review of the state-of-the-art sensorless control schemes over a wide speed range. Low-speed methods based on high-frequency pulse voltage injection and high-speed methods based on fundamental excitation are summarized to give readers a systematic categorization. An in-depth comparison of major sensorless control algorithms in estimation accuracy, robustness, universality, and parameter sensitivity is presented. Finally, the existing challenges and future trends are discussed.